Resistance unit for electric circuits.



W. A. CHRYST.

' RESISTANCE UNIT FOR ELECTRIC CIRCUITS.

APPLICATION FILED AUG-4,1913.

i 1,227,038; Patented Mayzz, 1917.

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UNITED sTATEs PATENT oiirEIoE.

WILLIAM A. OHEYsT, OE DAYTON, OHIO, AssIGNOE' To T11-E :OAYTON ENGINEERING i LABORATORIES COMPANY, A CORPORATION OE OHIO.

RESISTANCE UNT FOB. ELECTRIC CIBCITS.

To all whom it may concern:

Beit known that I, WILLIAM A. CHRYsT,

ya citizen of the United States of America,

tion.

This invention relates to an improvement in resistance units for electric circuits, and more particularly to a unit of this type, which will be especially adapted to be combined with the circuits of an ignition system.

Among the objects of the present invention, is to provide. a resistance unit which will be simple and economical to manufacture, and which may be readily assembled in the ordinary electric circuit.

Further objects and advantages of the present invention `will be apparent from the following description, reference being had to the accompanying drawings, wherein a preferred form of one embodiment of the present invention is clearly set forth.

In the drawings:

Figure 1 is a diagrammatic view` of the electric circuits and connections embodied in one form of the present invention.

Fig. 2 is a view in elevation of the distributing unit of the system.

Fig. 3 is a plan view of part of the distributing unit, with a portion of the resistance unit shown in section. A Fig. 4 1s a s1de view of the resistance un1t.'

Fig. 5 is a view along the edge of the resistance unit.

Fig. 6 is a view of one of the contact elements of the resistance unit.

Fig. 7'is a view showing a modified form of the resistance unit.

As has been explained in the co-pending applications of Charles F. Kettering, Serial No. 621,512, filed April .17, 1911 (Patent No. 1,171,055), and Serial No. 643,547, filed August 11, 1911, an ignition system is disclosed wherein there is provided a resistance unit adapted to perform certain functions, which are clearly described and claimed in the aforementioned applications and to which references may be made for further details. i'

The present invention particularly relates to the construction and mounting of the unit carrying the resistance; It is desirable that specification of Letters ratent.

Patented May 22', 1917.

Application filed August 4, 1913. i SerialNo. 782,886.

this unit be so arranged that it may be readily assembled or dis-assembled with any suitable circuit in such a manner, that that poi'- tion of the unit which acts as a carrier for the resistance will act as a guard for the resistance wire, and prevent accidental contact therewith. The advantage of this will be obvious when it is understood that the resistance wire at times is heated to 'a high degree.

At the same time it is 'notadvisable to ,fully inclose the resistance unit, inasmuch as it is desirable to expose the wire to the atmosphere so as to employ the effects thereof to assist in the cooling'of the resistance coil.

By referring to the drawings and more particularly `to Fig. 1, it will be seen that the source of current may be either a gener-V ator, as shown at 20, or a storage battery, as

' the line between the primary winding 23,

and the timing and distributing agent 30.

Supposing that the engine is running under its own power and the switch 25 is operated to close the ignition circuit, the timer contacts 27 and 28 will be successively opened and closed by the engine operated timer cam 29, thus successively making and breaking the ignition circuit.

Durin the period that the circuit is closed, t e iow of current from either the battery 21 or the generator 20 will pass through the primary winding 23 of the induction coil, resistance unit 26, contact plates 27 and 28, to the ground connection 22, back to the battery, through the ground connection 22. It will, of course, be obvious that the sparking impulses may be obtained by breaking the circuit by the operation of the timer cam or in any other suitable manner, such as a current interrupter of the type shown and described in the patent to Charles F. Kettering, No. 1,040,349, October 8 1912.

The distributer unit 30 is so arranged that it will select the proper cylinder to cause sparking therein, at the proper time. It will, of course, be understood that the timer cam 29 is operated mechanically by connection with the engine in the usual manner and it will further appear that if the engine should stop at such a point as to leave the timer cam in position to close the ignition circuit, that a rapid depletion of the current source would normally occur.

However, by having the resistance unit 26 inserted in the circuit and 'preferably located between the induction'coil and the timer, the current will only continue to flow until the resistance unit becomes heated, inasmuch as this unit is preferably made of materials of such properties that the resistance thereof increases with an increase in its temperature. Thus, a flow of current greater than a certain predetermined maximum through the ignition circuit will cause the temperature of the resistance unit to rapidly increase, and

f in consequence of its increasing temperature,

the resistance will rise in proportion.

One method of constructing the resistance unit is shown in Figs. 2 to 6 inclusive. Referring to Figs. 2 and 3, it will be seen that the contactv plate 27 of the timer projects outwardly through the timer housing and is insulated therefrom by means of the sleeve 32. The projecting end of the plate or stud is screw threaded as at 35 and is adapted to receive a tubular clamping element 36, which is so arranged that it receives and carries a hollow bushing 38, made of insulating material. This bushing is so formed that it has a core or insert 39. This insert 39 may be said to form the terminal post for carrying the spring terminal 40.

The terminal or binding post 4() may be of any suitable construction, as for instance, as is shown in the U.l S. patent to Charles F. Kettering, No. 1,089,771, dated March 10, 1914.

The resistance unit 26 consists of a disk made of any suitable insulating material and having an aXial opening 43, which is of such diameter as to readily pass over the bushing 38. The periphery of this disk 41 is grooved as at 42, and is adapted to receive the coil of resistance wire 47. The groove 42 is of such depth that the outer edges of the disk will extend beyond the resistance coil. This acts as a protection against accidental or inadvertent contact being made with the unit and at the same. time permits the resistance coil to be practically uncovered, so as to leave the same open to the atmosphere to secure the cooling effects thereof.

Referring to Figs. 4, 5 and 6, detail views of the resistance unit are shown, from which it will be noted that the insulated disk 41 is provided with a series of perforations or openings, through which the arms of the spiders 45 and 46 are adapted to pass in a manner `described hereinafter.

The contour of the spiders or contact plates 45 and 46 are substantially the same and therefore the detail construction of only one of these Contact elements will be described. The plate 45 comprises a. body portion having a central aperture and provlded with arms 45a, which are adapted to pass lthrough certain of the openings formed in l the disk 41. These arms are so spaced apart which is adapted to be positioned on the opposite face of the disk 41 from that upon which the spider 45 is positioned, has its arms so arranged that they will pass through the other openings in the disk 41 from those through which the arlns of the spider 45 pass. Thus, it will be seen that each of the Contact plates or spiders are entirely insulated from each other.

In order to connect the respective spiders with the opposite ends of the resistance coil 47, one of the arms on each of said spiders is elongated so that it will extend out beyond the periphery of the disk 41 and is bent into such position as to be readily secured to the opposite ends of the said coil.

A shoulder 49 is provided on the `opposite faces of the disk 41, upon which the respective contact plates or spiders 45 and 46 are adapted to rest, thus tending to prevent any accidental shortcircuiting between the plates 45 and 46, and at the same time it presents the body portion of the spiders in such a manner that a good electrical Contact may be made, respectively by the portion 40l of the terminal post, and the tubular clamping element 36, on the respective spiders.

The resistance unit, when in position, is slipped over the insulating bushing 38. This brings one of the contact plates 46 and 45 into Contact with the clamping nut 36, said clamping nut being in the circuit with the Contact plates of the timing mechanism. The opposite contact plate of the resistance unit forms the surface against which the terminal post 40 is screwed, thereby making the circuit connection, and also clamping the resistance unit in a rigid position.

It will be seen from the above description that when the current passes through the circuit up to the terminal post 40, its fiow l will be as follows: through the portion 40 of the terminal post, to the spider 46 and thence to the resistance coil 47, via the elongated arm 46, around the resistance coil to the arm 45b and thence to the clamping element 36, to the timer contact plate 27.

It will, of course, be understood that the4 system may be supplied with the usual condenser 33 across the timer contact points, which will tend to prevent sparking at these points..

In Fig. 7 there is shown a modification of the resistance unit having a disk 50, with a claims.

series of holes 51, located near its edge. 'A resistance coil is wound from one hole around the outsideedge of the disk and back into the next adjacent hole. Any suitable amount oit Wire can thus be wound around the disk until the complete circumference of said disk is filled, as shown in the drawing.A

` A cnt'act plate 52, is mounted on each side of the disk and are insulated from each other, said contact plates forming terminals for the extremities of the resistance coil, and also contacting surfaces for the clamping nut 36 and the terminal post 40.

While I have set forth one preferred form of the present invention, it will be understood that the `foregoing description and the accompanying drawing is not intended as a limitation of my invention, but that I reserve the right to make whatever changes in the elements and combination of elements, `comprising the .present invention, as may come Within the scope of the appended I claim- I 1. In a device of the character described;

uniti; and contact plates on the opposite faces of said disk andadapted to be electrically connected with the opposite ends of the resistance unit.

2. In a device of the character described, the combination with a disk of insulating periphery of said disk; insulating members extending beyond said resistance unit for protective purposes; and contact plates secured to the opposite faces of said disk, each 'of said contacts being electrically connected ythrough openings formed in said disk, the

openings for the arms of one of said contact plates being spaced apart from and independent of the openings for the arms of the other contact plate. y

In testimony whereof I aiiix my signature in the presence'of two subscribing witnesses.

, WILLIAM A. CHRYST. Witnesses: Y

J. W. MGDONALD, 0.. D. MOWRY.

' material;l a resistance unit mounted on the 

